This is a pre Keith Harte owned 1975 Ducati 900SS. First year for 900 Supersport and only 246 were built in combination with the ‘75 750SS.  The ‘75 SS is the only Ducati that shares the ‘74 750SS frame. Also the first 900 Supersports were made for production racing. They featured a fiberglass tank with 40mm Dellorto carbs, Conti Silencers, no turn signals and GP style right side shift. At the time you can also order them with the Imola upswept pipes as shown in some photos. They were the real superbikes of the 1970’s. With less than half of 1975 900SS built compared to the 1974 750SS Greenframe it makes the 1975 900ss the most rare of the Supersports.
This particular example was slightly modified by Keith Harte in the 70s. He disassembled the motor and built it with high performance Ducati racing parts and also nickel plated the frame. It also won a Canadian championship with rider John Connel from Oakville, ON, Canada. I recommissioned the bike approximately 5 years ago giving it a new set of shoes, some elbow grease, carb and brakes rebuild and some TLC. I ride it approximately twice a year without any issues. Thanks for looking and good luck.